Herbarium Digital Library

Palanan Wilderness Area

Category: Critical Plant Sites
Date Posted: 2005-12-26


The Palanan Wilderness Area contains one of the few remaining extensive blocks of rain forest in the Philippines. A variety of vegetation types occur within Palanan Wilderness Area, including lowland evergreen rain forest, lower montane forest, forest over limestone, forest over ultramafic soils, beach forest and mangroves.

Lowland and hill evergreen rain forests are the dominant forest types, covering an estimated 70% of the area, and occurring between 200m and 800m. Dipterocarps, such as Hopea negrosensis, Shorea Polysperma, S. suqmata, and Anispotera thurifera, dominate the canopy. Pterocarpus indicus occurs in marginal areas. Diospyros philippinensis is also abundant. Epiphytes, especially orchids, are common.

Lower montane rain forest covers an estimated 15% of the area, and occurs from 900m to the summit. Dominants include members of the genera Lithocarpus, Syzygium, Schefflera, Rhododendron and Vaccinum. Theaceae, Clethraceae and Elaeocarpaceae are also well-represented. Pinus kesiya occurs in significant numbers. Emergent trees, such as Agathis philippinensis, grow to 30m or more, but generally montane forests are lower in stature than lowland forests. Terrestrial epiphytic ferns and mosses are abundant.

Forest over limestone covers about 10% of the area, and is found in coastal areas, particularly at the southern part of Palanan Point. The dominant species are Vitex parviflora, Pterocarpus indicus and Garuga floribunda. These are semidecidious, shedding their leaves from February to April.

Forest over ultramafic souls also occurs in coastal areas, such as at Dinapigue, where the soil is shallow, with poor water holding capacity, and has high concentration of metals, but is poor in nutrients. The forest is stunted and the ground layer is dominated by members of Cyperaceae and Compositae.

Mangroves are confined to inlets in the estuary of Palanan River, the intertidal mudflats, sandflats and saline lagoons in Callawan and Sabang, near the mouth of Palanan River, and in the lagoons and coves at Bicobian and Dimasalansan. Nipa swamps, dominated by Nypa fruticans, also occur here.

Beach forest occurs along the coast on sandy or rocky substrates. The dominant species are Casuarina equisetifolia, Terminalia catappa, Barringtonia asiatica, Caesalpinia nuga, Erythrina variegata and Pterocarpus indicus. Crinum asiaticum, Acacia farnesiana, Ipomoea pes-caprae, Wedelia biflora and Mikania scandens are also common.


It is estimated that there are 1500 species of vascular plants in Palanan Wilderness Area and that, of these, more than 50 species are locally endemic and over 100 species are endemic to the Philippines. Numerous endemic and rare species are restricted to Sierra Madres mountain range. Many species are restricted to particular vegetation types within the area.

Useful Plants

The forest of the Palanan Wilderness Area contain important gene pools of many species of timber treesm including dipterocarps, Pterocarpus indicus (narra) and Diospyros spp. (kamagong). Species of rattans, belonging to such genera as Calamus and Daemonorops, are also plentiful in the forests. Agathis philippinesis provides a resin which is collected by the inhabitants. The highly attractive (and endangered) jade vine, Strongylodon macrobotrys, which has vivid turquoise flowers, grows in the area. Orchids, peperomias and aroids are among other highly attractive ornamental species.


Palanan Wilderness Area is threatened by expansion of towns, illegal squatters, over-exploitation of forest products, and by selective logging by local people.

The main towns (Maconacon, Palanan, and Davilacan) had an estimated population of around 21,170 in 1990. Between 1980 and 1990, the annual growth rate was 2.03% mainly as a result of immigration. The expansion of settlements and agricultural lands encroaches upon tropical lowland evergreen rain forest and other adjacent vegetation types. Technically, the settlements are illegal, since the Timber License Agreements (TLAs) of the three logging companies previously operating in the area were cancelled, and the Letter of Instruction which established the Wilderness Area prohibits human occupancy for development activities. Most agriculture around the settlements is permanent, but kaingin (chafing cultivation) occurs on a small scale.

A major threat is over-collection of ornamental plants (such as orchids) and plant products (such as rattan and resin, the latter primarily collected from (Agathis philippinesis). Such over-exploitation has increased at an uncontrolled rate as demand and prices have risen. So far, there have been no restrictions imposed by the government.

Illegal logging, though selective and small scale, is expected to intensify. Dipterocarps are the favored timber trees. If left uncontrolled, such logging will further degrade the forests of Palanan. The possibility of granting Timber License Agreements to meet domestic and world demands for timber or wood products cannot be ruled out, since Wilderness Area contains one of the last remaining dense primary forests in the country. With insufficient supply of timber now coming from the country's secondary growth forests and tree plantations, primary forests, such as those of Palanan Wilderness Area, are in imminent danger from large-scale commercial logging activities.

Mining of chromite, gold, copper, manganese and nickel is a potential threat, but fluctuating export prices have so far prevented further exploration in the area.

Feasibility studies on building roads to enhance the accessibility of towns isolated by the Sierra Madre range are currently underway. If roads were to be built there could be both direct and indirect impacts on the forests, and the area would be opened to squatters and further tree cutting.


Palanan was declared a Wilderness Area in 1979. The area includes within its boundaries various forms of protected areas, including "mossy" forests, protection forests, critical watersheds, proclaimed watershed reservations which support existing government dam projects or domestic water supply facilities, mangrove forests needed for the foreshore protection and for the maintenance of estuarine and marine life, and "species forests" (exclusive habitats of rare and endangered species). The Letter of Instruction which established the Wilderness Area prohibits human occupance and other development activities within the boundaries of the protected area, except for the purposes of recreation, education, research and conservation.

In 1964, the Divilacan Foreset Reserve (249.7 km?) was established to serve the needs of wood production, soil protection, and other forest uses. The reserve includes forests within the Palanan Wilderness Area in the municipalities of Ilagan, Palanan and Tumainini.

In 1986, mining and prospecting permits were suspended within Palanan Wilderness Area. However, despite the above measure, illegal occupancy and extractive activities still occur within the protected area.

Palanan is proposed as National Park Integrated Protected Areas System for the Philippines. National Park status will help to strengthen its protection. It is planned to train forest managers and rangers to help implement conservation measures, and to involve local people in sustainable management of natural resources. Zoning, currently lacking in all protected areas in the country, will help to define prescribed uses within specific area within Palanan. These will include protection zones, regeneration zones, areas of settlement and public service zone.

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